Recently, the progress in the semiconductor laser technology is remarkable. Such semiconductor laser technology is applied to various electronics equipments used in the recording/playing of the optical disc, or the information communication using the optical fiber, and the like. In recent years, the stacked type semiconductor laser device capable of obtaining the high-power laser by arranging a plurality of semiconductor laser elements to stack them in the horizontal direction has been developed.
In the stacked type semiconductor laser device, the semiconductor laser elements each of which is sandwiched between the copper tungsten members are stacked in the horizontal direction, and the light converging lens is arranged on the semiconductor laser elements respectively.
A related art is disclosed in Japanese National Publication of International Patent Application No. 2009-524223.
The copper tungsten member cannot obtain a sufficient thickness precision and a sufficient surface precision (surface roughness). Therefore, it is difficult to stack a plurality of semiconductor laser elements at a narrow pitch with good precision. For this reason, particularly when an arrangement pitch between the semiconductor laser elements is made narrow, misalignment is easily caused at the time of arrangement of the lens on each semiconductor laser element. As a result, it becomes difficult to construct the stacked type semiconductor laser device with high precision.